Stroke Structured Abstract - S #21
Caution: Splints may increase muscle spasticity in the hand
CITATION: Mathiowetz, V., Bolding, D. J., & Trombly, C. A. (1983). Immediate effects of positioning devices on the normal and spastic hand measured by electromyography. American Journal of Occupational Therapy, 37, 247-254.
LEVEL OF EVIDENCE: IIC2c
What are the immediate effects of a volar resting splint, a finger spreader, a firm cone, and no device on four hemiplegic patients and eight healthy persons?
Nonrandomized repeated measures design
Authors: "Balanced design sequence for devices"
SAMPLING PROCEDURE/INCLUSION CRITERIA
The stroke subjects had moderate to severe spasticity in the impaired wrist and fingers (stretch reflex was elicited in the first 2/3 range of motion as wrist or fingers were rapidly and passively extended).
All hemiplegic subjects were medically stable with no cardiac problems or uncontrolled hypertension.
Eight healthy subjects, aged 25 to 40 years, were tested.
N = 4 stroke (+ 8 healthy)
Male = 2
Female = 2
Mean age = 43.75
LCVA = 3
RCVA = 1
Attrition = NR
NR = Not Reported
Electromyographic activity of the flexor carpi radialis (FCR)
Electromyographic activity of the flexor digitorum profundus (FPD)
Condition 1: Volar resting splint
Condition 2: Finger spreader (a 6.5cm thick piece of foam rubber with five holes spaced to hold the fingers and thumb abducted)
Condition 3: Firm cone
Condition 4: No device
WHO DELIVERED INTERVENTION
FREQUENCY & DURATION
After the positioning device was put on, subjects were allowed a 2-minute rest period to adapt to the positioning device and to allow the EMG activity to return to baseline level. During the first 10 to 15 seconds of test recording, each subject squeezed 80%± 10% maximum voluntary contraction of grip with their unaffected hand, which caused overflow to the impaired side. During the following 45 seconds of the test recording, the subjects relaxed with the grasp meter still in their unaffected hand. After the test recording was completed, the positioning device was removed. After a 2-minute rest period the next positioning device was put on and the same procedure repeated.
For subjects with stroke:
There was no significant difference in EMG activity recorded for either muscle among the different conditions (FDP: F[3,9] = 2.90, p = .09, r = .67; FCR: F[3,9] = 3.07, p = .08, r = .71). There was high variability among the subjects, which, together with the small sample, could have obscured any effect. There was a trend of higher EMG activity in both muscles for the volar splint condition.
For healthy subjects:
There was no significant difference among conditions for the FDP (F[3,21] = 1.93, p = .16, r = .35). There was significantly greater electrical activity for the FCR, which, if the subjects were spastic, would be an indication of worsening of spasticity, under the condition of the finger spreader compared with no device (F[3,21] = 3.37, p = .04, r = .62).
Effect sizes could not be calculated from the information provided.
The statistical analysis showed no significant differences among the conditions for stroke or healthy subjects.
Within Groups/Conditions/Times: Not tested
THREATS TO VALIDITY
Small sample size may lead to Type II error (no difference when in fact there was an obscured difference). Effect sizes indicate that this may have been the case; that is, the effect sizes, calculated from probability level, were large for stroke subjects and moderate to large for the healthy subjects.
The procedure of using overflow generated by maximum grasp of the unaffected hand may or may not be equivalent to "natural" spasticity seen in hemiplegic subjects under various conditions of daily living.
Results showed significantly greater EMG activity of the FCR for the finger spreader condition compared with no device in normal subjects during the grasping period. Hemiplegic subjects did not show significantly less EMG activity when using positioning devices, compared with no device. In fact, the volar splint appeared to increase the EMG activity while the subjects were grasping with their unaffected, unsplinted hands.
The results of this study suggest that occupational therapists should be cautious when providing stroke patients with positioning devices to decrease spasticity because the devices may in fact increase muscle activity.
Terminology used in this document is based on two systems of classification current at the time the evidence-based literature reviews were completed: Uniform Terminology for Occupational Therapy Practice-Third Edition (AOTA, 1994) and International Classification of Functioning, Disability and Health (ICIDH-2) (World Health Organization [WHO], 1999). More recently, the Uniform Terminology document was replaced by Occupational Therapy Practice Framework: Domain and Process (AOTA, 2002), and modifications to ICIDH-2 were finalized in the International Classification of Functioning, Disability and Health (WHO, 2001).
This work is based on the evidence-based literature review completed by Hui-ing Ma, ScD, OTR, and Catherine A. Trombly, ScD, OTR/L, FAOTA.
For more information about the Evidence-Based Literature Review Project, contact the Practice Department at the American Occupational Therapy Association, 301-652-6611, x 2040.
Copyright 2003 American Occupational Therapy Association, Inc. All rights reserved. This material may be reproduced and distributed without prior written consent.